Method for forming transverse welded seams between vertically oriented workpieces having v-shaped groove and bevel

ABSTRACT

The welded seams are formed between facing edges of vertically oriented plate sections by submerged arc welding. The bottom edge of an upper section is formed with intersecting bevelled faces defining a V-shape nose in cross-section, and the upper edge of a lower thick plate section is formed with intersecting sloping faces defining a V-shape upwardly opening notch in cross-section. The sections are placed with the apices of the V-shape crosssections in substantial alignment vertically to define opposite facing welding grooves having a common welding groove root. The faces defining the welding grooves are arranged at angles such that the welding groove sides diverge outwardly and upwardly from the root. Molten weld metal is progressively deposited along the welding grooves by submerged arc welding while the welding powder is supplied to the grooves both before and behind the pool of molten weld metal. The apparatus includes a welding wire feed guide, contact jaws for conducting current to the welding wire, a conductor for connecting the contact jaws to a source of welding current, and a powder feed pipe in the form of an inverted Y which is fixedly connected with the welding wire feed device. The outlet openings of the powder feed pipe are arranged, respectively, before and behind the contact jaws in the direction of weld formation. A pressure gas may be supplied to the powder feed pipe in advance of the Y junction.

United States Patent Fischer et al.

[ Dec. 4, 1973 METHOD FOR FORMING TRANSVERSE WELDED SEAMS BETWEEN VERTICALLY ORIENTED WORKPIECES HAVING V-SHAPED GROOVE AND BEVEL [75] Inventors: Hans Fischer, Numberg; Herbert Hellendrung, Oberhausen, both of Germany [73] Assignee: Gutehoffnungshutte Sterkrade Aktiengesellschaft, Sterkrade, Germany [22] Filed: June 28, 1972 [2]] Appl. No.: 267,046

Primary Examiner-R. F. Staubly Assistant Examiner-George A. Montanye Att0rney.lohn J. McGlew et al.

[ 5 7 ABSTRACT The welded seams are formed between facing edges of vertically oriented plate sections by submerged arc welding. The bottom edge of an upper section is formed with intersecting bevelled faces defining a V- shape nose in cross-section, and the upper edge of a lower thick plate section is formed with intersecting sloping faces defining a V-shape upwardly opening notch in cross-section. The sections are placed with the apices of the V-shape cross-sections in substantial alignment vertically to define opposite facing welding grooves having a common welding groove root. The faces defining the welding grooves are arranged at angles such that the welding groove sides diverge outwardly and upwardly from the root. Molten weld metal is progressively deposited along the welding grooves by submerged arc welding while the welding powder is supplied to the grooves both before and behind the pool of molten weld metal. The apparatus includes a welding wire feed guide, contact jaws for conducting current to the welding wire, a conductor for connecting the contact jaws to a source of welding current, and a powder feed pipe in the form of an inverted Y which is fixedly connected with the welding wire feed device. The outlet openings of the powder feed pipe are arranged, respectively, before and behind the contact jaws in the direction of weld formation. A pressure gas may be supplied to the powder feed pipe in advance of the Y junction.

6 Claims, 2 Drawing Figures Pmmnntc m 5,777. 105

sum 2 or 2 FIGZ METHOD 'FOR'FORMING TRANSVERSE WELDED SEAMS BETWEEN VERTICALLY ORIENTED WORKPIECES HAVING V-SHAPED GROOVE AND BEVEL FIELD AND BACKGROUND OF THE INVENTION This invention relates to a method and an apparatus for the formation of welded seams extending in a transverse direction, between thick plate cross-sections, particularly when joining metal tank sections andforged rings utilizing the submerged arc welding procedure.

Heavy apparatus and pressure tanks, for example, reactor vessels, frequently are of such size that they must be initially formed of several components which must be transported, as singleparts, to'the construction site, because of their great weight and large dimensions. When the individual sections areassembled and welded to form tanks, it is frequently necessary, on the construction site because of lack of space, to effect submerged arc welding operations in the transverse position.

Heretofore, such welding operations have been carried out usingonly manual electrodes, particularly on thick alloyed plates such as tank sections and forged rings. However, this is uneconomical in view of modern welding methods, such as submerged arc welding or shielded arc welding.

The disadvantages of the present manual welding are substantially low output and poor quality of the welded material, for example, slag inclusions, pore formation, and crater cracks, and bonding defects at the flanks of the seams.

SUMMARY OF THE INVENTION The objective of the present invention is to provide a welding method and apparatus permitting welding utilizing the submerged welding procedure for the formation of transversely extending welded seams, that is seams which extend in a direction which is perpendicular to the axis of a tank, of tank sections, or of forged rings, even in the case of thick alloyed plates, and which avoid the above-mentioned disadvantages.

A further object of the invention is to provide such a method and apparatus utilizing the submerged arc welding procedure.

For an understanding of the principles of the invention, reference is made to thefollowing description of a typical embodiment thereof as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the Drawings:

FIG. 1 is a cross-sectional view of the seam form in accordance with the invention; and

FIG. 2 is a perspective view of the apparatus embodying the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT 45. The root width a on the side of the larger groove In accordance'with the invention, this problem is solved by producing a welding groove form at the facing plate edges, with the lower surfaces of the welding groove form sloping inwardly and downwardly toward each other to define a V-shape notch in cross-section. The welding powder is supplied or deposited both before and behind the welding pool, if necessary by using a gas under pressure. Advantageously, the angles of the sloping edge portions defining the welding groove have a value of l2-30.

In accordance with the invention, the apparatus for performing the invention includes a powder feed pipe in the form of a Y-pipe, with diverging outlet ends, supported on the guide for the welding wire, the outlets of the powder feed pipe being arranged before and behind the lower end of the welding wire guide. A special advantage of the invention is the provision of a pressure gas supply connected to the powder feed pipe at a point before the outlet ends of the. pipe diverge from each other.

An object of the invention is to provide an improved method for forming transverse welded seams between thick plate cross-sections.

Another object of the invention is to provide an improved apparatus for performing the method.

portion is about 20mm. It will be noted that the lower edge 1 of the upper workpiece is formed with intersecting bevelled faces defining a V-shape, downwardly facing nose in cross-section.

The upper edge 2 of the lower workpiece is formed with intersecting sloping faces defining a V-shape upwardly opening notch in cross-section, these faces extending at angles between 25 and 12 to the horizontal, so that the pouring and holding of the welding powder is facilitated. The magnitude of the aperture angle a, the magnitude of the root width a, and the angle B of the faces of the upper edge of the lower workpiece provide a very favorable ratio between a very small welding volume and a minimum cutting volume. This is of paramount importance for the economy of the method, particularly when welding transverse seams.

The root widtha of the deeper welding groove, to the right in FIG. 1, correspondsto the root width b of the shallower welding groove, to the left in FIG. 1. In contrast to the root width a, the magnitude of the root width b has been selected to be 10mm higher in order to obtain, after filling the deeper weld groove, to the right in FIG. 1, with deposited weld metal, a better accessibility to remove, for example, the unwelded seam root c by planing or grinding. It will be noted that, in effect, the apices of the two V-shape sections, namely the nose and the notch, are substantially alignted vertically, although possibly offset a little bit relative to each other.

The apparatus of the invention is shown in FIG. 2, and is used for performing the method of the invention. The welding powder feed pipe 4 is connected rigidly with the wire feed guide 3, and is so arranged that the welding powder is supplied in sufficient quantities both before and behind the welding pool or welding point, even with normal weights of the powder charge. This is particularly true for welding on the upper welding groove edge, where the welding powder, pushed away by the current contact jaws or nozzle 5, which is missing in the supply range, is supplemented through the second outlet opening 6a of the Y-pipe 7. The Y- shaped powder supply pipe 4 is eliptic in the range of the outlet openings 6, 6a, with the longer diameters of the ellipses extending in the welding direction and with the smaller diameters of the ellipses corresponding to the diameter of the current nozzle or jaws 5. By virtue of this, a reduction of the radius of action in the seam joint can be avoided, and an optimal height of the powder charge can be maintained, which is absolutely necessary for a pour-free and slag-free welded joint.

in order to ensure a uniform powder covering, even at shallower pouring angles in the upper and deeper seam regions, the powder feed is effected with carbon dioxide gas under pressure. The gas supply pipe is indicated at 8, and communicates with the powder feed pipe 4 above the point of diverging of the discharge legs of the latter.

All metallic components of the powder feeding means are formed of non-magnetic material, so that the magnetic field, existing during welding in deep seam joints, cannot have any adverse effect on the pouring behavior of the welding powder; Powder feed pipe 4 is displaceably mounted, by means of a holder 9, on the insulated or dielectric welding wire feed guide 3. The contact jaws or current nozzle 5 is arranged in the same plane as the outlet openings 6 and 6a of pipe 4, and between these outlet openings. The welding current supply line for the entire apparatus is indicated at 10.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

l. A method of forming transversely extending welded seams between facing edges of vertically oriented thick plate sections by submerged arc welding, comprising forming the bottom edge of an upper thick plate section with intersecting bevelled faces defining a V-shape nose in cross-section; forming the upper edge of a lower thick plate section with intersecting sloping faces defining a V-shape upwardly opening notch in cross-section; positioning the plate sections with the apices of the V-shape cross-sections substanially in alignment vertically to define oppositely facing welding grooves having a common welding groove root; and progressively depositing molten weld metal along the welding grooves by submerged arc welding while supplying the welding powder to the grooves both before and behind the pool of molten weld metal in the welding grooves.

2. A method of forming transversely extending welded seams, as claimed in claim 1, including supplying a gas under pressure to the welding powder to effect proper feeding thereof.

3. A method of forming transversely extending welded seams, as claimed in claim 2, in which the gas under pressure is supplied both to the welding powder deposited before the pool of molten weld metal and the welding powder deposited behind the pool of molten weld metal.

4. A method of forming transversely extending welded seams, as claimed in claim 1, in which said intersecting sloping faces are at angles of 12 to 25 to the horizontal.

5. A method of forming transversely extending welded seams, as claimed in claim 1, wherein the welding grooves defined by said bevelled faces and said sloping faces increase in width upwardly and outwardly.

6. A method of forming transversely extending welded seams, as claimed in claim 1, in which one of said welding grooves is relatively deep and the other of said welding grooves is relatively shallow; the root width at the base of the relatively shallow welding groove being substantially greater than the root width at the base of the relatively deeper welding groove. 

1. A method of forming transversely extending welded seams between facing edges of vertically oriented thick plate sections by submerged arc welding, comprising forming the bottom edge of an upper thick plate section with intersecting bevelled faces defining a V-shape nose in cross-section; forming the upper edge of a lower thick plate section with intersecting sloping faces defining a V-shape upwardly opening notch in cross-section; positioning the plate sections with the apices of the V-shape cross-sections substanially in alignment vertically to define oppositely facing welding grooves having a common welding groove root; and progressively depositing molten weld metal along the welding grooves by submerged arc welding while supplying the welding powder to the grooves both before and behind the pool of molten weld metal in the welding grooves.
 2. A method of forming transversely extending welded seams, as claimed in claim 1, including supplying a gas under pressure to the welding powder to effect proper feeding thereof.
 3. A method of forming transversely extending welded seams, as claimed in claim 2, in which the gas under pressure is supplied both to the welding powder deposited before the pool of molten weld metal and the welding powder deposited behind the pool of molten weld metal.
 4. A method of forming transversely extending welded seams, as claimed in claim 1, in which said intersecting sloping faces are at angles of 12* to 25* to the horizontal.
 5. A method of forming transversely extending welded seams, as claimed in claim 1, wherein the welding grooves defined by said bevelled faces and said sloping faces increase in width upwardly and outwardly.
 6. A method of forming transversely extending welded seams, as claimed in claim 1, in which one of said welding grooves is relatively deep and the other of said welding grooves is relatively shallow; the root width at the base of the relatively shallow welding groove being substantially greater than the root width at the base of the relatively deeper welding groove. 